As disclosed in Wilson U.S. Pat. No. 2,816,113 2-[(hydroxyimino)methyl]-1-methylpyridinium chloride (Pralidoxime chloride, 2-PAM chloride) is useful as an inhibitor of cholinesterase and is particularly useful as a specific antidote against lethal alkyl phosphate intoxication.
Aqueous 2-PAM chloride solutions have a tendency to be unstable, particularly at elevated temperature. Hussain U.S. Pat. No. 3,629,425 proposes the stabilization of 2-PAM salts (e.g. 2-PAM chloride) by adding an inorganic acid in an amount sufficient to reduce the pH of the 2-PAM chloride to a pH within the range of 1.0 to 3.0 and then storing the thus stabilized 2-PAM chloride.